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Forwarding scheme whereby mail to a subdomain is filtered?

1997-06-11 07:00:00
[Procmail-L:ers, sorry for the low Procmail content. I'd love to see
this solved in Procmail so I thought I'd run this by the Procmail list
in addition to posting to Spam-L.]

As you people may have noticed, I am nowadays posting with a From:
address which is actually a "virtual" address at a forwarding service.
This is nice because the address will work even after I graduate /
move / change employers / whatever and I can redirect it anywhere I
want, even at very short notice. It is less nice, however, because my
current University account has a fairly good SMTP-level spam filter,
whereas the iki.fi forward service has no filters at all. After I
started using the iki.fi address on mailing lists and Usenet, an
increasing number of spams have -- predictably -- arrived via the Iki
address, thus circumventing any SMTP-level filtering on the host where
I actually read my mail. 
  Last time I asked the Iki folks about measures against spam, they
flatly stated they'd refuse to filter their users' mail. Apparently,
the problem has escalated generally, not just in my personal mailbox,
because now when I brought up the question again, they said they're
thinking about it.
  However, they would like it to work on an address-by-address basis,
where era(_at_)nospam(_dot_)iki(_dot_)fi would be subject to filtering, while
era(_at_)iki(_dot_)fi would not be filtered at all. It also seems that they will
still not do SMTP blocking at any point.
  The problem is that the whole service is run pretty much as a
volunteer effort, so one issue is also whether any proposed solution
can be implemented easily and not end up causing a lot of maintenance
chores. Finally, you cannot expect to have more than one machine for
mail handling at your disposal.

Here's what they would like to see: 
 1. If a message is for user(_at_)iki(_dot_)fi, proceed to 3.
 2. If a message is for user(_at_)nospam(_dot_)iki(_dot_)fi, run it through 
some sort
    of content filtering, and generate a bounce if warranted.
 3. Do normal /etc/aliases alias expansion etc and proceed with mail
    processing as usual.

Does anybody have any ideas about how this can be accomplished? The
current forwarding is done simply via /etc/aliases if I understand
correctly -- there is no such concept as a "virtual user's" home
directory at any point, from the perspective of the iki.fi machine. 
  While I'm generally knowledgeable about Procmail, the admin side of
things is not something I have any practical experience of. As far as
I can tell, you get to run Procmail only after alias expansions etc
have been performed. Is this correct? 

Personally, I'd love to see them adopt SMTP filtering, but this is
apparently not going to happen. So if anybody has comments about how
this scheme could be implemented, and/or suggestions for a better
scheme (I guess where users can still decide for themselves whether
they want filtering or not, without generating work for the management
each time they change their mind), I'm sure I'm not the only one who
would be grateful. (The Iki service presently has some 1400 users.)

/* era */

-- 
Defin-i-t-e-ly. Sep-a-r-a-te. Gram-m-a-r.  <http://www.iki.fi/~era/>
 * Enjoy receiving spam? Register at <http://www.iki.fi/~era/spam.html>

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